You know that feeling when you walk up to a door and push but it’s a pull door? Or vice-versa? It turns out it’s not your fault.

After an ongoing battle with a particular door in his office, Vox journalist Joe Posner decided to look into why this happens and how to fix it. The answer is surprisingly simple. Oh, and these doors are called Norman doors.

Why Norman doors? Because they’re named after Renaissance man Don Norman for identifying them in his book The Design of Everyday Things. Posner travels across the country to learn more from the man himself.